Honey is delicious. Smooth and sweet. If it sits in your cupboard too long, it could start to crystallize. This doesn't mean it is bad, you just need to fix it, decrystallize it. It is very easy to do, and doesn't take that long.

Step 1: Supplies

Not much is needed to fix your crystallized honey.

Crystallized Honey
Glass Jar (if honey is in a plastic container) - cover is optional and if you use one, make sure you don't put it on the jar very tight, keep it loose
Saucepan / Pot / an Asparagus Pot also works GREAT for this as it will use much less water
Stove
Water

We will be using the stove top, I do not know if you can use a microwave to do this, but I would think you could.

Many people in the comments also recommend just throwing your container of crystallized honey in the dishwasher and letting it sit through cycles until it is back to normal! Just make sure it is closed tightly so it doesn't leak :)

Step 2: Move to Glass Jar and Heat

If your honey is in a plastic jar, move it into a glass one. You need to be able to put it in a pan of water on the stove. I used a knife to stab the crystallized honey and scooped out what I could with a spoon that fit through the mouth of the container.

Once it is transferred to the glass container, put it in a pot of water on the stove. Now turn the stove on to low to medium heat. You want it barely simmering, no boiling [mine got a bit too hot at one point (started to try to boil) and the jar was trying to dance around in the pan so I turned it down until it stopped doing that]. Do not submerge the whole jar. I recommend having the water level up to the level of the honey if you can. Also, it is good to avoid having the jar sit on the bottom of the pan by using a trivet as sharpstick suggested in the comments. If you use an asparagus pot, it already has a nice basket in it you can put the jar on :)

Note: If you put the lid on, like I did, make sure it isn't super tight, you want to make sure air can escape and the jar doesn't explode.

Let it sit in the water for 20-30 minutes. Feel free to stir it as it sits there to help it along (probably don't want a lid on if you are going to stir it). I think mine was there for 35, but I was just being careful since it was my first time doing it. You can just set a timer and let it sit if you want. I used tongs to lift my jar up once in a while and swish the honey around to watch its progress.

Once you no longer see any crystals forming, you can turn it all off and take the jar out to cool. Your honey shouldn't recrystallize, but if it starts too, you can heat it up again on the stove until it looks right, then move it to a bowl of warm water. This will prevent it from cooling too fast.

I don't know how old of honey it will work on, but if my label is right, my honey is 4 years old and I was still able to de-crystallize it. Don't judge. It's just sugar.